The Sparrow by Mary Doria Russell
This book was riveting and extremely emotional. It is about what happens when Earth receives contact from another planet in the form of music. The Jesuits plan their own mission to go contact them. It is also a great deal about what happens afterwards to the people who come home.
The story alternates between two time periods: setting up the flight (and eventually their arrival on the planet) and the aftermath of the journey (after their return). At first this sort of bothered me since you knew a fair amount of the outcome of the mission well before it "happened" in the book and I thought it gave away more than I wanted it to. (Several other books use the technique better, e.g., Slow River and The Dispossessed.) But it ended up being a very effective technique and I can see why the author decided to go that route.
There is clearly a lot of evaluation of faith and how you reconcile your faith with horrible events. The title of this post, Deus Vult (God wills) came up frequently. I can't help but feel that I would have gotten a bit more out of it if I was more religious, although some of the reviews on Amazon would tend to dispute that. There are a lot of questions brought up that are never resolved.
The alien societies were well thought out & interesting, although not the focus of the book. The humans were really smart and funny and clever and mostly easy to identify with. There is a sequel, which I understand deals a bit more with the aliens than this one did. I think that will be interesting, since there is a lot more to be said about their society.
This is an excerpt from the novel, if you're interested.